better installation

README.md

@@ -23,6 +23,12 @@ sudo apt install rrdtool
 sudo ./install.sh
 ```
 
+The executable application files are installed under
+`/opt/cheap_system_monitor`. Configuration remains in
+`/etc/cheap-system-monitor.conf`, and the RRD database remains under
+`/var/lib/cheap-system-monitor` so code, configuration, and mutable data stay
+separate.
+
 Edit `/etc/cheap-system-monitor.conf` to choose network interfaces,
 mountpoints, and the graph directory. For example, use
 `mountpoints = /, /boot/firmware, /mnt/data` to monitor two additional disks;

install.sh

@@ -11,8 +11,8 @@ command -v rrdtool >/dev/null 2>&1 || {
     exit 1
 }
 
-install -d /usr/local/lib/cheap-system-monitor /var/lib/cheap-system-monitor
-install -m 0755 system_monitor.py generate_graphs.py /usr/local/lib/cheap-system-monitor/
+install -d /opt/cheap_system_monitor /var/lib/cheap-system-monitor
+install -m 0755 system_monitor.py generate_graphs.py /opt/cheap_system_monitor/
 install -m 0644 systemd/*.service systemd/*.timer /etc/systemd/system/
 if [ ! -e /etc/cheap-system-monitor.conf ]; then
     install -m 0644 cheap-system-monitor.conf.example /etc/cheap-system-monitor.conf

systemd/cheap-system-monitor-graphs.service

@@ -4,5 +4,5 @@ After=cheap-system-monitor.service
 
 [Service]
 Type=oneshot
-ExecStart=/usr/local/lib/cheap-system-monitor/generate_graphs.py
+ExecStart=/opt/cheap_system_monitor/generate_graphs.py
 User=root

systemd/cheap-system-monitor.service

@@ -4,5 +4,5 @@ After=local-fs.target
 
 [Service]
 Type=oneshot
-ExecStart=/usr/local/lib/cheap-system-monitor/system_monitor.py
+ExecStart=/opt/cheap_system_monitor/system_monitor.py
 User=root